engineers are great for any Cov late game. use on BC, Hunters, Scarab, buildings, etc
my personal preference is 13 Engineers + whatever ^^
Edit: making sure you know that I meant Ngs + Brute + BC in your case cause I kinda sounded like an idiot bringing up Ngs outta no where :-p
2-0 me-DC Shizface in standard 1vs1
1-0 me-DC Shizface in deathmatch 1vs1 on 2vs2 map :D